Generally, they're not as sought after as Base Set, but the rarest first edition cards from these sets will still be extremely expensive, especially in good condition
The benefit for casting those higher-costed creatures is arguably greater, though, as Helga draws a card, gains a life, and gets a +1/+1 counter for each of these creatures cast
At the extreme, you might eschew one or more colors entirely
Sauron, the Dark Lord has one of the most difficult ward abilities to deal withplayers have to sacrifice a legendary artifact or legendary creature to even target it
With an understanding of the premise, lets get into the deck
It later came back as Oblivion Stone, which costs a bunch more mana and can't take out exotic lands